There has been a trend during the past few years to provide products that will sanitize, clean and/or deodorize lavatory fixtures such as toilet bowls and urinals as they are used. All of these products involve some system of a sustained and controlled release of the active ingredient (germicide, cleaning agent, deodorant, etc.) into the toilet bowl or urinal each time that the fixture is used and/or flushed.
Commonly used are so-called rim blocks or urinal blocks, which are manufactured by compressing or melting sublimable material, such as para-dichlorobenzene, camphor, naphthalene and adamantane into blocks. Examples of such systems are disclosed in U.S. Pat. Nos. 3,943,243, 3,903,022 and Japanese Pat. No. 75 24,449. These systems have certain limitations. Their effective life span depends on the rate of sublimation rather than on use. Sublimable blocks, which are formed by compression, are also limited as to the amount of active ingredients (germicides, surfactants, fragrance, etc.) they can hold. Attempts to incorporate higher levels of such ingredients usually fail either because such ingredients tend to be pressed out during manufacture or because soft, crumbly blocks are produced. Sublimable materials also have characteristic odors. In order to cover these odors, fragrance selection is limited to extremely strong fragrance compounds which may not be that desirable from an olfactory point of view. There is also some concern with the fact that the block material itself sublimes into the room and is inhaled along with the fragrance. For example, para-dichlorobenzene is currently the subject of environmental concern and its use for purposes wherein the possibility exists for human exposure may be restricted in the future.
Other solid toilet system sanitizers, cleaners and deodorizers have been manufactured by compressing granular or powder mixtures of surfactants, hydratable salts, (e.g., Na.sub.2 SO.sub.4, NaHSO.sub.4, Na.sub.2 B.sub.4 O.sub.7, NaP.sub.2 O.sub.7, MgSO.sub.4, etc.) and other additives where desired (e.g. dyes, perfumes, and/or other minor components) or by cooling a molten mixture of the above ingredients. See, for example, German Pat. Nos. 2,162,790, 2,407,947, 2,907,029 and U.S. Pat. Nos. 4,149,986, 4,096,593 and the references cited therein. Such molded surfactant blocks suffer from many of the same drawbacks and limitations mentioned for the sublimable blocks. The action of flushing or other turbulence that is required to release the active ingredients often causes the block to soften and crumble. It is also known that surfactants suppress the rate of evaporation of volatile materials such as fragrances. (U.S. Pat. Nos. 4,250,165 and 4,320,873 and the references cited therein.) Surfactant blocks do not, therefore, release their volatile components (e.g. fragrance components) as well as sublimable blocks, and have been found to be inferior to the sublimable blocks for deodorizing toilet bowls and urinals.
A need exists for a product which would deodorize like a sublimable block, release other active ingredients, germicides, surfactants, etc., upon demand like a molded surfactant block, and which would release the fragrance material into the surrounding area over a long period of time without at the same time releasing undesirable products into the air or water. This invention provides such a product.